With all the knowledge on edge geometry out there, why are factory edges still so common?

[vivi]

Something that's been niggling at me lately are all the posts regarding catra tests, total cards cut and the influence of edge geometry on the numbers achieved in these tests.

BBB has done a great job making posts showing just how much influence edge geometry has on edge retention. Basic idea being the thinner the edge, the higher the edge retention, until catastrophic failure is reached.

This is common knowledge now.

The idea has been pushed since before I got into high end knives 20-25 years ago,but mainstream acceptance of the idea how grown much since those days.

Back in the early to mid 2000's on knife forums it was often said, incorrectly, thicker edges have better edge retention.

Now we have a wealth of data from catra tests and other controlled cutting demonstrations showing the opposite is true.

BUT.

The majority of people still run factory edges on their knives.

I'm not talking about average folks that may not even carry a pocket knife, and if they do it's a $5 knife from a gas station.

I'm talking about people dropping $200-600 on 15V and other exotic steels.

I don't get the point of chasing such high performance but then being unwilling to go thinner than about 20-17 degrees per side.

An analogy I've used a lot is to me it's like buying a nice sports car but then keeping the tires at 25PSI and using basic unleaded gas.

It's leaving performance on the table after going out of your way to purchase a performance oriented piece of gear.

Some of my earliest posts here were about this subject. Here's a thread from 2008 I made about taking my UKPK down to a full convex reprofile, under 10dps at the edge - viewtopic.php?p=436487#p436487

Been beating this drum for years but it seems like it still isn't catching on.

It's something I think about often when I'm talking about steels, edge retention etc. here.

Someone sharpening their factory edged S30V knife on a sharpmaker using the 20 degree slots could honestly being getting only 50% of the edge retention I get from my S30V Military 2 sharpened to about 12 degrees per side.

That's a big,big difference.

Deadboxhero / BBB has tons of posts on the subject. viewtopic.php?p=1819892#p1819892



So S30V, a steel a lot of folks here and elsewhere scoff at, will actually out cut a lot of more modern super steels due to how I sharpen it.

This is just talking about pure edge retention. I haven't even touched on how my reprofiled knives will take less effort to cut the same material, or will be more ergonomic to use for certain tasks because I don't have to tilt my wrist as much (carving wood with a 20dps edge vs 10dps feels much different).

Feels strange seeing so many maxamet, 15V, 20CV, M390, S110V etc. knives run thicker than a 420HC Buck 110.....and their owners being perfectly fine leaving them that way.

Anyone here that wants a good example of "geometry cuts" should order themselves a Kiwi 172. It's a $5 kitchen knife using bottom of the barrel mystery stainless, but boy does it cut.

[ejames13]

One reason might be that a lot of people sharpen on fixed angle systems, and many of those can't go below 15dps.

Another reason is probably how much bad info is circulated on the interwebz. Just like the notion that drawing a freshly ground apex through a block of wood is a legitimate means of burr removal.

[Evil D]

I think that recent thread about the destroyed Nilakka is a hint at why, even if that's an extreme example. Things like this are usually designed for the worst case users or they become warranty claims.

This reminds me of production tunes on cars vs race tunes. Even with high performance cars, you can almost always tune them to make even more power but then you start to lose reliability. With knives, I guess they need to be sure that a guy won't fracture out a chunk of his blade while carving a hard branch.

[Guts]

Seeing how a lot of manufacturers (other than Spyderco obviously) do their plunge grinds leads me to believe a lot of people have just never sharpened a knife before including a lot of designers. If they did, there'd be a ton of complaints about plunge grinds. Expecting users like that to change the geometry of their knives almost seems out of the question.

Most knife people just aren't sharpeners plain and simple, which is fine. They either aren't good at, are uniformed about/intimidated by, or can't be bothered to sharpen. Plus I think most people have never experienced a crazy hand sharpened edge so they don't know what they're missing anyway, unaware there's levels of sharpness well above what you get from the average factory edge.

Some people that just want the thing to do what it was designed to, even if its not in the most optimal configuration. I'm like this with cars. I just want to go from point A to point B. I take care of my car, but I don't care about anything else as long as it works.

[WilliamMunny]

Vivi,

I think it comes down to three things:

1. It's much easier to sharpen to a steeper DPS but you need to start taking a lot of steel off to thin the shoulders down. I don't think most knife owners have the equipment or skill to take a knife to 15dps let alone 10-12 dps.

2. TOUGHNESS - It comes down to your use case. If you are using your knife hard, outdoors, cutting zip ties, whatever, then a 17dps edge might work for you. There would just be less chance of chipping or knife damage. In a warehouse environment something with 20dps might be a better choice.

3. How often can you sharpen your knife? I know BBB mentioned he wanted a knife in the field that could dress large game without being sharpened because access to sharpening in the field is not always easy and time consuming. It's in part where he wanted an upgrade from K390 and looked to 15v. On the other hand, if you have daily easy access to a good knife sharpening system you might not be as worried about edge retention.

Also wanted to mention Sal is running his REX-121 at 12dps with no issues... just awesome.


Finally, a question for @Sal, why 17dps from the factory? Is that just a safe angle to minimize damage/complaints or is that the optimum angle for Spyderco Knives?

[nerdlock]

Honestly, some just want to collect things and leave them at that state, right out of the factory.

Some also do not want the hassle of sharpening high performance steels, or do not have the time and patience to do so.

Me, I just like to collect some, and use some. I've sharpened some steels to steep angles, and some I just leave at factory bevel. Most I don't touch at all.

[SpyderEdgeForever]

Vivi sal David and all: you are ofcourse free to disagree with me but I believe all knife companies and makers both factory and custom except for razors should just willingly ban all Hollow Grinds and stick to Convex Flat Saber and Appleseed Grinds on all knives fixed and folded.

[TkoK83Spy]

I think a lot of what we see here is many people have so many knives, they don't care to test the steel or it's limits because they keep switching knives every day. If they are going to spend time working on their knives, it's usually swapping pocket clips, scales, washers/bearings/cages. I've noticed it too, does make me wonder why so many need the latest and greatest when they won't even put it through the paces. We've seen people intimidated to tweak a pivot screw, let alone take a knife to the stones. I think that's a major factor as well, intimidation and fear of messing up. But...how will you ever learn if you don't try!? Sharpening is truly an entirely different world/element to the hobby and I think many people are missing out on that. 45 knives in 30 steels and 0 with a custom edge...you're not learning anything about the steel you're paying all this extra money for.

I get excited seeing the group of guys here that put some amazing edges on their knives, even the guys that go for the mirror finish. Not something that personally strive for, but I know you spent time working on your edge and learning about the steel and abrasives being used. There's opportunity to learn each and every session. I figure, they are just knives...is it really going to matter and make you lose sleep if you get a couple scratches on your blade while learning? Personally, I find sharpening sessions to be relaxing. Play some music, have a beer and get to work. Muscle memory while free handing is a wonderful skill to have as well. That only comes with practice!

[Jesla]

Vivi sal David and all: you are ofcourse free to disagree with me but I believe all knife companies and makers both factory and custom except for razors should just willingly ban all Hollow Grinds and stick to Convex Flat Saber and Appleseed Grinds on all knives fixed and folded.

I freely disagree… I want more hollow, especially full hollow grinds and a lot fewer flat grinds. When I made knives, I ground full hollow grinds 95% of the time. Also, they just look better… more organic… premium.

Geometry plays a far more important part of the equation and geometry is highly governed by use. Use, as in what you use it for, a pry bar/screwdriver or a cutting tool.

[RustyIron]

I don't get the point of chasing such high performance but then being unwilling to go thinner than about 20-17 degrees per side.

Who the heck knows why people do what people do. Just pick up the newspaper and you'll see what I mean (assuming you can actually FIND a newspaper in 2025).

I suspect that most folks stick with what the companies provide. If a blade comes from the factory with 30 degrees, that's what they'll try to copy when they sharpen the knife. If a Sharpmaker comes with 30 degree and 40 degree capability, that's what the majority of users are going to do. For the average jamoke who just knows to take his knife and rub it on a rock, then going to a more acute angle can be a grueling exercise that doesn't yield impressive results.

I think the question might best be directed at someone who can effect change. Spyderco, why don't you whip some CQI on the Sharpmaker? Dump 30 and 40, and give us 22 and 27. This might be a bit of a challenge for casual users with 30 degree knives, so Spyderco would have to start making blades that were more acute. Why not do that? Why not go to skinny-angle blades?

S.A.B.R.E.
Spyderco Advocates for Bevel Refinement & Enhancement

[barnaclesonaboat]

I think this is a thoughtful question @vivi and at least in my brain @Guts 's answer rings with some truth. I also think that a lot of people just haven't yet used a next-level sharp knife... let alone used a pocket knife sharpened to 10-14 degrees per side, used long enough to lose the keenness and have the resulting opportunity to realize how well that now 'dull' knife is still cutting.

I've been a life-long knife-carrier and user and to be honest totally crap sharpener, and I didn't have my aha moment until just a few years ago when I was re-bitten by the spider bug and buckled up for long enough to gain some sharpening skills. I took my S110V PM2 to 12-13 degrees per side, and even with a decent mirror edge, as the edge 'broke down' a bit it just stayed super aggressive! Cuts and cuts and cuts. Now I take most of my hard-steel knives down into this range - it really is a performance level that I had no idea existed until I used a knife with a steel/edge like this for a few months. When I finally have a block of time to dig into my Sage5 REX121, I'm planning to aim for 10-12 ish degrees per side.

[ykspydiefan]

For myself, it's unbalanced priorities. I have spent a lot on knives and little on sharpening. I think the consumer habit is trained for the new stuff, like a new knife. A fancy new fixed angle sharpening system would be great, but its a lot of cash and really the start of a new hobby. It's a different investment in time and learning.

Perhaps the knife hobby and sharpening hobby are really more separate hobbies than they appear to be.

[Mushroom]

I think a lot of what we see here is many people have so many knives, they don't care to test the steel or it's limits because they keep switching knives every day. If they are going to spend time working on their knives, it's usually swapping pocket clips, scales, washers/bearings/cages. I've noticed it too, does make me wonder why so many need the latest and greatest when they won't even put it through the paces. We've seen people intimidated to tweak a pivot screw, let alone take a knife to the stones. I think that's a major factor as well, intimidation and fear of messing up. But...how will you ever learn if you don't try!? Sharpening is truly an entirely different world/element to the hobby and I think many people are missing out on that. 45 knives in 30 steels and 0 with a custom edge...you're not learning anything about the steel you're paying all this extra money for.

I get excited seeing the group of guys here that put some amazing edges on their knives, even the guys that go for the mirror finish. Not something that personally strive for, but I know you spent time working on your edge and learning about the steel and abrasives being used. There's opportunity to learn each and every session. I figure, they are just knives...is it really going to matter and make you lose sleep if you get a couple scratches on your blade while learning? Personally, I find sharpening sessions to be relaxing. Play some music, have a beer and get to work. Muscle memory while free handing is a wonderful skill to have as well. That only comes with practice!

I definitely fit into this category. It's not that I don't care but also, I don't care.

I care enough to know what I'm carrying and why but I don't care to push the limits of any steel. I also don't chase any steel, so I'm not entirely in the designated group of people here. That's not why I carry knives though. I carry knives because I need to cut things and the factory edge angle has always been sufficient enough to do what I need. If I change the edge angle, it's still going to cut the exact same things I already cut. I know how to sharpen my knives when I need to but I'm just not focused on comparing the differences between edge angles.

Basically I'm obsessed with Spyderco and I have too many knives to use the same one everyday. I'm obsessed with Spyderco for many reasons but my primary focus is design. Personally, I don't buy these high dollar knives because they're inherently more capable than other knives - I buy them because they're works of art! I'm not ashamed to protect my investment. If I spend $60 on a Delica and $600 on a Paysan - Best believe that Paysan won't be getting used in the same way that $60 Delica will be.

I don't need high performance tires on my car to get from point a to point b in much the same way I don't need to change the angle of my knife's edge to cut what I need to cut. High performance tires would improve my grip while driving but if the majority of my driving is through neighborhoods, then I don't need to take corners at 70 mph.

For myself, it's unbalanced priorities. I have spent a lot on knives and little on sharpening. I think the consumer habit is trained for the new stuff, like a new knife. A fancy new fixed angle sharpening system would be great, but its a lot of cash and really the start of a new hobby. It's a different investment in time and learning.

Perhaps the knife hobby and sharpening hobby are really more separate hobbies than they appear to be.

This is very well put and I wholly agree.

[sal]

I might add; most of the folks here, know quite a bit about knives and edges. Far more than the average knife buyer. The ratio of knife afi's to the general knife buying pubic is probably quite small?

I also agree that the knife hobby is different than the sharpening hobby, which is probably smaller. In fact, the divisions in the knife world could probably be more than just those two?

sal

[Jeb]

To me, there are those of us like really like knifes, good ones anyway.

Then there are those of us that spend a lot of time and money just sharpening and really honing the edge on these knife.

Then there are the gearheads, like me I love how everything works together, this includes the first two categories above also. I am not bashful at taking a die-grinder to any of my knifes if they are screaming at me too lol...

We like all the really cool special hardware and Loctite to help secure it. We like to take things all apart, toothbrush clean with alcohol and lube everything as we reassemble.

We want to be able to buy all the little components as well. The special tools that is required for some of these components, we want a full set of them as well. I just acquired a new Smock today and it has this new special Axle bolt head, that I have no idea where to get that lol.

So there are those of us that are really infected lol... Yes I do take meds for this but they are not very affective and I take a horse size doze three times a day, just to keep my horns and tail from coming out and really being a problem lol.

[zhyla]

I'm talking about people dropping $200-600 on 15V and other exotic steels.

There's a huge spectrum in enthusiasts buying knives. A large amount of people are buying 15V because they heard it's the best and it's got different letters and numbers than the knives they have. Lots of people also don't have a firm grasp of geometry. To many, concepts like wear resistance and toughness are sort of magical properties ("this steel has a +2 against batoning") rather than physical processes that they understand. These aren't bad people or dumb people, it's just the level at which they interact with or understand knives. Not everyone has the inclination to become an edge nerd.

I really think Spyderco has made this worse. They're meeting the demands of their customers so you can't really fault them. But there is little rationale for making knives in 15 steels at the same time. Part of it is compounded by the global manufacturing realities (e.g. using VG-10 in Japan and 154CM in USA, or any number of equivalent steels) and our need to believe in steels as being magical.

If all Spydercos came in a few steels then we'd be madly trying to optimize the geometry rather than buying more knives in newer steels only to realize that, huh, they all kind of cut the same if they have the same geometry.

I will also confess that I haven't really looked into modifying edge angles much. Or at least not in any scientific way. I recently got a cheap digital angle gauge and that's enabling me to actually measure what angle I'm putting on something, so that's good. But my Chaparral LW, which is in my pocket 90% of the time, is still running the factory geometry. Which leads me to my final point:

The factory geometry works well, and most people actually don't need the bleeding edge performance because they're just opening boxes.

[Skywalker]

Because sometimes I do stupid or careless stuff with my knife, or don't have a better tool, and have put dings in factory edges (or edges sharpened at factory angles) on 8cr, VG-10, M390, 20CV, Hap40, CPM M4...

If I have it for long enough it will likely get somewhat thinned out but oftentimes I'm just not in a huge rush to do that.

[Mage7]

One reason might be that a lot of people sharpen on fixed angle systems, and many of those can't go below 15dps.

This seems pretty likely, along with the misconception that one needs a fixed angle system to achieve a specific angle, or the difficulty achieving a specific angle without a higher level of knowledge and skill free-hand.

However I think the idea that one even needs to go for a specific angle is the biggest misconception of all. Because the "best" angle is going to depend on the steel, heat treat, etc. but also it's probably going to depend on the tasks it's expected to perform, and who knows how environmental factors may affect things too. A geometry that's good for green wood won't be for seasoned wood, and neither will be great for meat.

A good analogy: What is the best rate of speed to drive on ice/snow? The fastest speed you can go without losing traction. Likewise, the best angle is the most acute one can use without it denting, rolling or chipping so that the dulling all happens from abrasive wear. I know that when I am driving on really bad snow/ice, I tend not to pay much attention to the speedometer except just to check that I am in a specific range I know from past experience is where I want to be, but that expected range is usually dependent on the car, tires, etc. In fact about the only place the analogy breaks down is if you take the speed limit as a suggested default like one might take factory geometry, you'll likely end up in a ditch, whereas factory edges are usually pretty good safeguards--probably because the government doesn't have to honor any sort of warranty claiming it's safe to travel the posted speed limit.

I know a lot of people who suggest the only reason knife manufacturers don't use more acute edge angles is because end users will abuse them, so they'd end up with too many warranty claims. Well, I think there is a little bit of truth to that, but one can see how the average factory angles have sort of started to trend down from 25dps, then "performance" oriented companies aimed for 20dps, and then now you have Spyderco putting stuff out at 17 and 15. On the other hand, I think a lot of that also just tends to be because it's a lot less wear on one's tooling to grind a few hundred thousand blades at 25dps than at 15dps, so it's merely an economic choice sometimes even if a company doesn't have a reputation to protect. Whoever's manufacturing gas-station specials isn't grinding them so obtuse because they're worried about warranty claims.

When it comes to a reputable cutlery company like Spyderco, I tend to think they choose their factory geometries with optimum edge retention in mind, but they also have to anticipate what a huge expanse of different customers are going to encounter with the same knife. Coming up with a one-size-fits-all edge geometry is hard enough on its own, but then they also have to anticipate whether their user base will tolerate if that suggested-default fails catastrophically with major edge damage. I think people kind of tend to see the factory geometry as the best balance between performance and safety in unexpected use pressures because they know a good company will strive for that balance out of the box.

I'll make a flimsier analogy... I think the kind of person who worries about optimizing edge angle is the type of person who will take their suit to a tailor. On the other hand, most people are happy with something off-the-rack so long as they're not bursting out of the seams. Many times that probably seems like people are squandering a really good suit without the perfect fit, but I think some people actually enjoy finding the best fit they can find on the rack and enjoying the default.

Personally, I am an edge geometry junkie that free-hands edges as low as 12dps with +/- 2 degrees accuracy, but even I will sometimes just try out the factory geometry for a while. I have found factory geometry to usually be a pretty good starting point to go down from, seldom perfect, and never too thin.

[Bill1170]

Super-acute sharpening bevels, very thin BTE blades, and splinter-picker tips all share the same risks. Namely, they will be damaged by careless users and produce headaches for the maker and retailer alike. It’s not worth the hassle for a production knife company. So your options for high-performance geometry are either custom knives, building your own knives, or modifying production knives to suit your preferences. That last option is what I do because it’s affordable and with patience can be accomplished with hand tools like whetstones and the Sharpmaker.

[jwbnyc]

One reason might be that a lot of people sharpen on fixed angle systems, and many of those can't go below 15dps.

This seems pretty likely, along with the misconception that one needs a fixed angle system to achieve a specific angle, or the difficulty achieving a specific angle without a higher level of knowledge and skill free-hand.

However I think the idea that one even needs to go for a specific angle is the biggest misconception of all. Because the "best" angle is going to depend on the steel, heat treat, etc. but also it's probably going to depend on the tasks it's expected to perform, and who knows how environmental factors may affect things too. A geometry that's good for green wood won't be for seasoned wood, and neither will be great for meat.

A good analogy: What is the best rate of speed to drive on ice/snow? The fastest speed you can go without losing traction. Likewise, the best angle is the most acute one can use without it denting, rolling or chipping so that the dulling all happens from abrasive wear. I know that when I am driving on really bad snow/ice, I tend not to pay much attention to the speedometer except just to check that I am in a specific range I know from past experience is where I want to be, but that expected range is usually dependent on the car, tires, etc. In fact about the only place the analogy breaks down is if you take the speed limit as a suggested default like one might take factory geometry, you'll likely end up in a ditch, whereas factory edges are usually pretty good safeguards--probably because the government doesn't have to honor any sort of warranty claiming it's safe to travel the posted speed limit.

I know a lot of people who suggest the only reason knife manufacturers don't use more acute edge angles is because end users will abuse them, so they'd end up with too many warranty claims. Well, I think there is a little bit of truth to that, but one can see how the average factory angles have sort of started to trend down from 25dps, then "performance" oriented companies aimed for 20dps, and then now you have Spyderco putting stuff out at 17 and 15. On the other hand, I think a lot of that also just tends to be because it's a lot less wear on one's tooling to grind a few hundred thousand blades at 25dps than at 15dps, so it's merely an economic choice sometimes even if a company doesn't have a reputation to protect. Whoever's manufacturing gas-station specials isn't grinding them so obtuse because they're worried about warranty claims.

When it comes to a reputable cutlery company like Spyderco, I tend to think they choose their factory geometries with optimum edge retention in mind, but they also have to anticipate what a huge expanse of different customers are going to encounter with the same knife. Coming up with a one-size-fits-all edge geometry is hard enough on its own, but then they also have to anticipate whether their user base will tolerate if that suggested-default fails catastrophically with major edge damage. I think people kind of tend to see the factory geometry as the best balance between performance and safety in unexpected use pressures because they know a good company will strive for that balance out of the box.

I'll make a flimsier analogy... I think the kind of person who worries about optimizing edge angle is the type of person who will take their suit to a tailor. On the other hand, most people are happy with something off-the-rack so long as they're not bursting out of the seams. Many times that probably seems like people are squandering a really good suit without the perfect fit, but I think some people actually enjoy finding the best fit they can find on the rack and enjoying the default.

Personally, I am an edge geometry junkie that free-hands edges as low as 12dps with +/- 2 degrees accuracy, but even I will sometimes just try out the factory geometry for a while. I have found factory geometry to usually be a pretty good starting point to go down from, seldom perfect, and never too thin.

That. And sometimes you might want to go thicker not thinner